A conventional technique includes driving a display device with a Thin Film Transistor (TFT). For example, a Thin Film Transistor Liquid Crystal Display (TFT-LCD) generally includes a color filter substrate and a TFT array substrate. The TFT array substrate includes multiple pixel units, and each pixel unit is associated with one TFT. When a certain voltage is applied to the gate of the TFT, the channel is switched on, and an electric current flows from the source to the drain of the TFT. A certain voltage difference between a pixel electrode and a common electrode causes liquid crystal molecules to rotate by different angles, so as to create light and dark display in different areas.
However, the TFT is a photosensitive element. If a metal layer is provided on a side of the color filter substrate facing the TFT array substrate, e.g., a metal layer needs to be provided commonly when a touch-control structure is built in, the metal layer will reflect the light from a backlight toward the TFT array substrate. A leakage current, i.e., a photo leakage current, will occur when the light irradiates the channel. In this case, a voltage of the pixel electrode becomes different from a predetermined voltage, thereby resulting in an uneven display.